Bromodeoxyuridine (BUDR), a known radiosensitizing drug, is given as a continuous intravenous infusion and patients with high-grade brain tumors and other poorly radioresponsive tumors. The drug is infused for either 12 or 24 hours daily for up to 14 days with some patients receiving two separate infusions of BUDR. To date 16 patients with primary brain tumors and eight patients with other poorly radioresponsive tumors have been treated with a combination of BUDR and conventional fractionated radiation.